<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>03_固定定位</title>
    <style>
        .fu {background-color: #ff0}
        .fu>div {
            width: 100px;
            height: 100px;
        }
        .z1{background-color: #f00}
        .z2{
            background-color: #0f0;
            /*固定定位：会释放布局空间
            移动参照物：html根元素*/
            position: fixed;
            left: 0;
            bottom: 0;
        }
        .z3{background-color: #00f}
    </style>
</head>
<body>
    <div class="fu">
        <div class="z1"></div>
        <div class="z2"></div>
        <div class="z3"></div>
    </div>
</body>
</html>